Brake boosteb toe motoe



March 8, 1932. D. M. MARTINDILL BRAKE BOOSTER FOR MOTOR VEHICLES Filed Feb. 26. 1931 INVENTOR I Patented ,1932 i 1 j 1,84s,se6'

DONALD M. MARTInnrLn, or YOUNGSTOWN, onto BRAKE BOOSTER non Moron-versions" v: i

ApplicationlfiltaflFebruary 26, 1931; fSeri'al 110,518,323.

Usually v motor vehicles such a emotor trucks, are in use loaded beyond their rated capacity,

the brakes which the latter wereloriginally 5 not designed to carry. Thereforeit i'si rnec essary to amplify the service or-other brakes the increased load may be taken careof safe- 7 interposed betweenthe foot treadle or other actuating member and the brakes. V H I The object which I have in viewis the provision of a new and more -simplified booster mechanism, which easily and at smallcost may be applied to the brake mechanism of a of the drawings 1 represents one-of the side motor Vehicle, and which will be more effec- 20 tive in increasing the braking power and ef fect. Generally speaking my improved booster mechanism comprises a'lever of the first class and aleverlof the second class having mov-' .2 ing contactjwith ea'choth-er, the firstclass lever being the leverage lever which is connected to the brakes while thesecond class lever .is the pull lever which iiis connected to the foot treadle or other actuatingmember.

The leverage lever is angular or bentand is pivotally supported adjacent its angle, v

' bracket attached to the bar '1 and extending while its tail or the end which is unconnected to the brakes isfprovided with a perimetral edge which acts as a track upon which travels a roller carried by the pull lever, the angu-' larity of such track relative to the other end of the leverage lever determining the 16''.

verage which the pull lever, exerts on the leverage, 40

Pl a r .J

Preferably the" pull leveris'double so as to straddle .the tail of the leverage lever and the roller is mounted between the two members of the pull lever. Other novel featuresiof construction and also of arrangement of parts will appear from the following description.

In the accompanying drawings wherein I have illustrated a practical embodiment of and thus a burden is placed upon braking powerfof the of the vehicle so that This amplification is usually provided for booster? and lever and also the progressive in crease of such leverageas the brakes are ap-l by; a

the principles of invention, 1 is a broken plan view of thefchassisof amotor vehicle illustrating the front and rearbrakes, 1 i the treadlefor'operatingithe brakes andfmy' crating mechanism.

improved booster interposed in the br'akeop- 5 i Fig. 211s an enlarged plan view of the p er -mechanism. 1

Eigfil is a side'elevation ofthe sameglooking from the right in Fig.

v i big. at is-a si-le elevationof the leverage r leverwhich is connected to the equalizer shaft of the brakes. V

Fig. 5 is an elevation of the double pull v lever which is connected tothe t'readIeQ I Fig; 6' is' a viewsimilar toyFig. 2 but il- Qlustrating a different set up for the pull lever.

teferring first to Figsul to -5, inclusive,

bars or members of the vehicle chassis, and 2 and 3the front and rear wheels, which are provided with thebrakes 4'. The brakes are connected as by the links'5 to the cranksti of the equalizer shaft 7.3 Intermediate of its 4 length the-shaft 7 is provided with acrank V {hereinafter refer to it asthe treadle.

.10 represents a horizontally disposed inwardly toward the longitudinal'axis of the chass'is. Mou-nted on the inner end of said bracket is .a three. sidedboxing 11 having v parallel side walls12 which extend inwardly.

- l3-represents an-angular, lever pivotally mounted betweenthe walls 12am adjacent its angle as on the pin: l lxwhoseends are se-., curedin said walls; Thestem orouter end of said lev er is connected to the crankarm'B link lf) which may be provided with a turnbuckle 16 for length adjustment. The.

. lever 13' is the-lev age lever of the mecha-,

nism. I V V The pull lever comprises the twinlever's 17 whose inner ends areprovided with trunnions 18 journaled in bearing holes 18a in the walls 12. The members,17'strad'dlethe tail of the lever 13 and a roller l9"is"mounted 10o a turnbuckle 23 for length adjustment.

The angle of the lever lilis provided with,

an arcuate recess 24 in which the roller 19 engages when the brakes are released and when the treadle is depressed to apply the brakes, thein-it-ial movement of the "pull lever 1-7 in a counterclockwise direction in Figs. 1

sand 2 causes the roller torfirst climb the wall of said recessgthus takin-g up slack or lost motion and then to travel alon the *aerimctra'l edge of the tail of the leverlS, -.causing' 'said leverto also swing in acounterclocl wise direction and thus apply the brakes.

The inner ed 'e or track of the tail of the lever 13 is arcuaite and eccentric to the axis of the swing of the lever 17, sothat leverage is exerted on the lever 13 by the movement of the lever 17, and said track is so disposed that such leverage increases as the brakes are applied. The outer end of the track swings in with an increased curvature or rise, so that as the brakes are set the resistance of further movement is such as to inform the operator that the roller is traveling too far and adjustment is necessary.

It is evident that by providing the roller track with the proper angularity orcurvature relative to the other endof the lever 13 the desired amplification of theleverage exerted by the treadle may be obtained and such leverage may be caused to increase in the desired ratio. as the movement proceeds.

I have shown the walls 12 of the bozrlng 11 provided with a second pair ofahned journal holes 186 in which the trunnions 18 of the members of the levers 17 may be journaled. Thus the pull lever may be set, as shown H]. Fig. 6, so that theroller -W1ll not seat in the recess 2 when the brakes are released but will alwaysbe in contact with the track, and I thus the setting of the brakes begins when the pressure is first applied to the treadle.

'T-he two levers are each provided with two or more holes 25 for attachment of the connecting links, thus enabling the leverage exerted in connection with the two levers and also the relative leverage of the two levers to be varied and regulated. 7

My improved booster is of simple and in expensive yet durable and rugged construction. It may be quickly installed in the brake system of any motor vehicle and it provides means whereby the necessary amplification of the braking power may be readily obtained.

What I claim is 1. A brake-booster mechanism for motorvehicles comprising a support carried by the vehicle, a first class lever pivotally mounted intermediate or" its ends on said support and having one end linked to the brakes, a second class lever pivotally mounted at its inner end on said support and having its outer end linked to the brake-tread'le, and a roller mounted on said second class lever intermemounted adjacent its angle on" said support and having its outer end linked to the brakes, a second class lever having its inner end pivotally mounted on said support and having its outer end linked to the 'brake-treadle, and

"a roller mounted on the second class :lever ntermediate of its ends and riding on the lateral surface 01 the inner end ofthe first class lever.

3, A brake-booster mechanism for 1notorvehicles compr sing asupport carried by the vehicle, a first class leverpivotally mounted intermediate ofits ends on said support and having its outer'end linked to the brakes, a double second class lever pivotally mounted at its inner end on said support, and straddling the inner end of'the first class lever, the outer endof the second class lever being linked to the brake-treadle, and a roller :1 mounted between the members of the second class lever and riding on the lateral surface of the inner end of the second class lever.

4. A brake-booster mechanism for motorvehicles comprising a support carried by the vehicle, an'angu'l'ar first class lever pivot-ally mounted adjacent its angle on said support and havingone endlinked to thebrake's, a double second class lever having its inner end pivotally mounted on said support and straddling the inner end of the first class lever, the outer end 'o fgthe second class lever being linked to the brake-treadle, and a roller carried by t'hesecond-c lass lever intermediate of its ends and riding on: the lateral surface or the inner end of the first class lever.

'5. A brake-booster mechanism for motorvehicles comprising a housing mounted on the vehicle and provided with parallel walls, a

first class lever pivotally mounted intermediate of its ends between "said walls and havn' its outer end linked tothe brakes, a secon' class lever having its inn-er and pivotally mounted between said walls'and having its outer end linked to the treadle, and a roller mounted on the second class lever intermediate of. ts ends and riding on the lateral surface of the inner end of the first class lever.

6, brake-booster mechanism for motorvehicles comprising a housing mounted on the vehicle and provided with parallel walls, a first class lever pivotally mountedinterme diate of its ends between said walls ing its outer end linked to the brakes, a second class lever havingits inner endpivotally V a mounted between said walls and having its outer end linked to the treadle, said second class lever being double and straddling the inner end of the first class lever, and a roller mounted on the second class lever intermediate of its ends and riding on the lateral surface of the inner end of the firstclass lever.

7 A brake-booster 'mechanism for motorvehicles comprising a housing mounted on the vehicle and'having parallel walls, an angular first class lever pivotally mounted adjacent its angle between said walls'and having its outer end linked to the brakes, a second class lever having its inner end pivot-' said walls and having ally mounted between to the treadle, and a its outer end linked roller mounted on the second class lever intermediate of its ends and riding on the lateral surface of the inner end of the first class lever.

8. A brake-booster mechanism for motorvehicles comprising a housing mounted 011 the vehicle and having parallel Walls, an angular first class lever pivot-ally mounted ad-' jacent its angle between said walls and having its outer end linked to the brakes, a second class lever having its inner end pivotally mounted between said walls and having its outer end linked to the treadle, the second class lever being double and-straddling the inner end of the first class lever, and a roller mounted on the second class leverintermedr' ate of its ends and riding on the lateral surface of the inner end of the first class lever.

9. A brake-booster mechanism for motor vehicles, comprising a support, an angular leverage lever pivotally mounted adjacent its angle on sa1d support andhaving one end connected to the brakes and the other end of said leveragelever having an arcuate con 1 tact surface, a pull lever pivotally connected at one end to said support and having its other end connected to the treadle, and a roller mounted on the pull lever intermediate of the ends of said levervand arranged to travel on said contact surface as the pull lever is caused to swing, the curvature of said surface being eccentric to the axis of the pull levers movement.

10. A brake-booster mechanism 01 motor?- vehicles, comprising a support, an angular leverage lever pivotallv mounted adjacent its and ha'v- 0f February, 1931 end of,

travel on said contact surface as the pull lever is caused to swing, the curvature of said surface being eccentric to the axis of the pull levers movement, theouter end of said surface beingprovided with a riser to rapidly pletes its operative swing. I

11. A brake-booster mechanism for motorvehicles, comprising a support, an angular leverage lever pivotally mounted adjacent its angle on said support and having one end connected to the brakes and the other end of said leverage lever having an arcuate contact surface,'a pull lever pivotally connected at one end to said support and ,having its other end connected tothe treadle, and a roller mounted on the pull lever intermediate of the ends of said lever and arranged to travel on sa1d contact surface as the pull lever is caused to, swing, the curvature of'said surface being eccentric to the axis of the pull-levers movement, the inner end of said contact surface I being provided with a recess which is occu pied by the roller when the brakes are released.

Signed at Youngstown,'O., this 23dday M. MARTINDILLF ALD DON

70 increase the leverage as the pull lever com- 

